The invention relates to a device for distributing a flow of air in a duct of an installation for heating, ventilating and/or air conditioning a passenger compartment.
A device of this type generally comprises an electric motor capable of moving a distribution flap between a position for closing and a position for opening a duct of an installation of the abovementioned type.
The device further comprises a voltage source for electrically powering the motor. A control module, connected to the motor, usually regulates the electric power delivered for supplying the motor.
Such a control module, however, comprises a large number of components, including several active components, which complicate the structure of the module. Moreover, when the flap is immobile, especially in one of its open or closed positions, the control module cuts off the power supply to the motor. A set of electronic components is generally provided allowing time delaying of the duration of power supply when the control module cuts off the power supply to the motor, the flap having reached one of its opening or closing positions. Such time-delay electronics further encumber the structure of the known control modules.
The present invention aims to improve the situation.
According to the present invention there is provided a device for distributing a flow of air in at least one duct of an installation for heating, ventilating and/or air conditioning the passenger compartment of a motor vehicle, comprising:
a flap suitable for being moved between a position for closing and a position for opening the duct,
an electric motor for moving the flap,
a voltage-supply source, and
a power-regulation module,
wherein the power-regulation module comprises a first terminal connected to a first terminal of the motor, wherein the power-supply voltage is suitable for being applied between a second terminal of the regulation module and the second terminal of the motor, and wherein that the regulation module is configured so as to adjust the strength of the current passing through the motor, at substantially constant power-supply voltage, to a value below a threshold value when the flap is immobile.
Hence, the motor of the device according to the invention can be supplied with voltage permanently, which makes it possible to dispense with time-delay electronics of the type described above.
Advantageously, the regulation module is formed by at least one passive two-pole, preferably a positive-temperature-coefficient resistor.
According to another advantageous, optional characteristic of the invention, the power-supply source is configured to deliver a polarized voltage, and the regulation module includes a change-over circuit suitable for supplying the motor with a current which is a function of the polarity of the power-supply voltage.
Hence, in one preferred embodiment of the invention, the regulation module includes two positive-temperature-coefficient resistors, mounted in parallel and connected respectively to first and second diodes, inverted and each mounted in series with a resistor.
Advantageously, the polarity of the power-supply voltage delivered is:
of a first sign when the flap is in its closed position and/or in motion from its open position to its closed position, and
of a second sign, opposite to the first sign, when the flap is in its open position and/or in motion from its closed position to its open position.
In one advantageous embodiment of the invention, the regulation module and the motor, when the vehicle is in service, are supplied with a voltage which is substantially constant, at least in absolute value, and the regulation module is configured to adjust the strength of the current passing through the motor to a value below the abovementioned threshold value, when the flap is in one of its open and closed positions. dr
Other advantages and characteristics of the invention will emerge on examining the detailed description below, and the attached drawings, in which:
FIG. 1 represents an overall view of a device according to the invention, including a flap 4 for distributing an air flow F in a duct of an installation for heating, ventilating and/or air conditioning the passenger compartment of a motor vehicle;
FIG. 2 diagrammatically represents the electrical circuit of a module for varying the electrical power supply to the motor M of the device, according to a preferred embodiment of the present invention;
FIG. 3 diagrammatically represents a variation in the ohmic value of a positive-temperature-coefficient resistor, as a function of its temperature, such a resistor being used in the electrical circuit of the regulation module of FIG. 2; and
FIG. 4A diagrammatically represents the time-based profile of the strength of current i which passes through the motor M, when the flap 4 passes from an open position to a closed position P2;
FIG. 4B diagrammatically represents the time-based profile of the ohmic value of one of the resistors R1 and R2 of FIG. 2, when the flap 4 passes from an open position P1 to a closed position P2; and
FIG. 4C diagrammatically represents the time-based profile of the voltage at the terminals of the motor UM, when the flap 4 passes from an open position P1 to a closed position P2.